Electrostatic printers are known for printing large format drawings, for example. The printing paper is pulled off from supply rollers. Depending on the size of the drawings, two or more paper supply rollers having paper webs of a different width may be positioned for cooperation with the printer. The printing of the drawings takes place either relative to the sheet length or crosswise thereto.
Once the printing is completed, these large format drawings are folded by machines capable of handling such large formats. U.S. Pat. No. 5,045,039 (Bay), issued on Sep. 3, 1991, discloses such a folding machine. Such a machine folds large sheets of different sizes with different folding patterns and the sheets are so folded that the parts list or legend head of the sheet appears in the proper position on the folded sheet. In other words, for proper recognition of the drawing, the legend head must appear on the top sheet section of the folded sheet. For this purpose it is necessary that the sheets are fed to the folding machine in the proper positional orientation.
Further, it is known to program such folding machines in such a way that the number of folds to be formed may vary, depending on a length of the sheet. However, independently of the number of folds to be made it is always necessary that the legend head or parts list must appear on the top sheet section when the folding operation is completed and this requirement must be met independently of the lengthwise or crosswise orientation of the sheet prior to entering into the folding machine. This requirement that the legend head or parts list must appear in a predetermined position on the top sheet section of the folded sheet requires that, for example, in drawings that are printed on a sheet taken off from a wide roller in a longitudinal format, can be fed directly into the following folding apparatus. However, when drawings are printed onto sheets in a cross-format, that is with a half size, and the sheet has the same width from a supply roll having the same width, it is necessary that the sheet on its way to the folding machine is turned by 90.degree., for example, on a supply and sheet orienting table. Such orienting takes place in the plane of the drawing in order that the folding operation can be correctly performed. The same considerations apply where one or more paper rolls having a smaller width are used as the paper supply.
Swiss Patent CH 650,221 (Bay), issued on Jul. 15, 1985, discloses an apparatus for transporting sheets having a rectangular format, however, of different sizes. In such an apparatus it is necessary that the individual sheets in accordance with their format, travel so that the correct sheet edge forms the leading edge when such sheets enter a folding machine and/or an edge branching automat. The sheet transport takes place as an automatic feed advance by linearly effective transport elements such as rollers and the like. In order to assure that the proper edge forms the leading edge, sensors are provided for recognizing the sheet format. The sensors are arranged above the supply table and cooperate with an adjustable holding member which permits rotating of sheet of a certain format about a vertical eccentrically arranged axis, whereby the holding member forms the axis and transport elements then turn the respective sheet about the vertical axis on the table. The known apparatus works so slow for rotating large sheets and needs a large table for transporting the sheet in different directions.